1. Field of the Invention
An embodiment of the present invention relates to a secondary battery, and more particularly, to a secondary battery having a new member preventing an increase in the internal pressure of the secondary battery, thereby improving reliability characteristics including lifetime, etc.
2. Description of the Related Art
Recently, secondary batteries have been used as power sources of portable electronic devices in many fields, and accordingly, demands on secondary batteries rapidly increase. The secondary batteries may be charged and discharged several times and thus are economically and environmentally effective. Accordingly, the use of the secondary batteries is promoted.
Meanwhile, a secondary battery may be charged/discharged by an electrochemical reaction of a positive electrode plate, a negative electrode plate and an electrolyte in the interior of the secondary battery. When the charging/discharging of the secondary battery is performed, a side reaction occurs together with the electrochemical reaction. This side reaction results in deterioration of the secondary battery; therefore, the lifetime of the secondary battery is decreased. In addition, the side reaction causes gas to be generated in the interior of the secondary battery. The gas causes the secondary battery to be swollen by the increased internal pressure of the secondary battery, and causes the secondary battery to be exploded in a serious case. Accordingly, various studies have been conducted to eliminate gas generated in the interior of a secondary battery.